#[test]
pub fn position_test(){
    let text = "Xerxes";

    assert_eq!(text.chars().position(|c|c=='e'),Some(1));
    assert_eq!(text.chars().position(|c| c == 'z'), None);
}

//
#[test]
pub fn rposition_test(){
    let bytes = b"Xerxes";

    assert_eq!(bytes.iter().rposition(|&c|c==b'e'),Some(4));
    // assert_eq!(text.chars().position(|c| c == 'z'), None);
}